A solution of 4-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)phenylboronic acid (138 mg, 0.51 mmol), methyl 2-(3-methyl-4-(trifluoromethylsulfonyloxy)phenyl)acetate (Intermediate 12-2; 159 mg, 0.51 mmol) and tripotassium phosphate (162 mg, 0.76 mmol) in DME (3 mL), ethanol (1.5 mL) and water (0.5 mL) was degassed before addition of (1,1′-bis(diphenylphosphino)ferrocene)-dichloropalladium(II) (DCM adduct) (33.5 mg, 0.04 mmol). The reaction mixture was heated to 80° C., under nitrogen, and left to stir overnight for 16 hrs. The reaction mixture was allowed to cool to room temperature and then evaporated. The residue was partitioned between water (20 mL) and EtOAc (50 mL). The aqueous was re-extracted with EtOAc (2×10 mL) and the combined organics washed with brine (20 mL), dried (MgSO4) and evaporated to give crude product. The crude product was purified by flash silica chromatography, elution gradient 10 to 100% EtOAc in isohexane on 12 g silicycle column. Pure fractions were evaporated to dryness to afford ethyl 2-(4′-(6-carbamoyl-3,5-dimethylpyrazin-2-yl)-2-methylbiphenyl-4-yl)acetate (79 mg, 38.4%) as a colourless oil which crystallised on standing.
